Centering device for the cutting of sheet-metal disks



P 1943 E. HAMPF 30,577

CENTERING DEVICE .FOR THE CUTTING 0F SHEET-METAL DISKS Filed Feb. 25,1942 mvENT'oli.

fanzz 6257f aim Q 1 AT TORNEIYS 'vice for the cutting of sheet-metaldisks,

pointed pivot.

Patented Sept. 28, 1943 assent Hai sstad, Swedeng a company of Swedcn 1Application many '25, 1942,.Serial. 1

In Sweden January 13, 194.15

3 Claims. (01.164-71),

The present invention refers to acentering delarly in such plate cuttingmachines wherein the cutting members are arranged stationary, while arotary movement is imparted to the plate during the cutting operationabout the center of a known suffer from the disadvantage that the recessproduced by the pivot in the plate will be worn out or extended when theplate is being moved around, sothat a play will set in which may resultin that the cut disk will not be of an exactly circular shape. Theobject of the present invention is to preventthe of sheet-metal in acentered position during the cutting operation. To this end, thecentering pivot and the bed or matrix pertaining thereto are arranged,according to the invention, on pins adapted to be turned about thecentral axis, said pins being mounted in corresponding parts of themachine frame in a manner such that an axial movement may be imparted tothe pins to bring hemtoward one another when they are turned in the amedirection. By reason of the friction between the pivot and the beddingon the one hand and the piece of sheet-metal on the other hand, saidpins thus tend to clamp the piece of sheet-metal between the pivot andthe bedding in the process of cutting, whereby a play will beeffectively prevented.

The invention is illustrated in the accompanying drawing, wherein Figure1 shows a cross section of the centering device according to one form tof embodiment of the invention and Figure 2 represents a view inelevation thereof in another position of adjustment. I

In the drawing, 1 and i2 designate the upper one and the lower onerespectively of the two frame arms between which the sheet-metal isbeing advanced during the cutting operation, said arms carrying at theirouter ends the cutting members not shown in the drawing. On the sides ofsaid arms facing one another are secured guide rails 2 and Hrespectively extending radially in the longitudinal direction of thearms in a mutually parallel relationship. The centering device isadjustable to different radial distances along said guide rails throughthe agency of two runners 3 and lil which may be locked to therespective rails by means of fastening screws 4 and 9 respectively, theupper one of which is lefthanded and the lower one right-handed. Saidfastening screws are coaxially arranged and provided with central,internally threaded bores particuproduction of such play, and to ensuresteady retaining of the piece,

Means of this type as hitherto,

- matrix for the centering pin left-handed screw 8, whereupon theright-hand down'by means of the hand threaded in opposite I adapted toreceive the pins 5 and 8 to be screwed into the same. The

upper pin 5 is right-handed and the lower pin 8 left-handed. Thecentering pivot l is coaxially arranged in the pin 5 and rigidly securedto the latter. The pin 5 is also provided with a hand wheel 6. The upperend of the pin 8 is intended to serve as a bedding or I, and to thisendit is as usual provided with a. central conical i countersink.

. The sheet-metal to be cut is placed on the lower ed screw 5 is screwedwheel 6, so that the pointed end is pressed against the sheet metal.

of the pivot I When in the process of cutting the piece of sheet-metalis moved round, in a clockwise direction as viewed from above, theoppositely threaded pins 5 and '8 will, to commence with, be entrainedthrough friction by the sheet-metal at the rotary movement thereof, thesheet-metal being thus clamped still further between the manner toeffectively prevent the production of play between the sheet-metal 0nthe one hand and the pivot l and the pin 8 on the other hand. Throughthe friction between the pins 5 and B on the one hand and the screws 4and 9 on the other hand the pins 5 and 8 at their movement will transfera turning moment onto the fastening screws 4, 9. Since the latter screwsare of the screws against the guide rails 2, II will thus be ensured.The cutting operation having been completed the sheet-metal is loosenedby the pin 5 being turned back by means of the hand wheel 6. Figure 2shows the device at a fully turned-back position of the pin 5.

Obviously, the arrangement described may also be used in plate shearingmachines wherein the cutting members rotate about the centering axiswhile the sheet-metal is kept stationary during the cutting operation.

I claim: r

1. A centering device for cutting of disks in plate cutting machinescomprising a centering pivot, a matrix for cooperating therewith,coaxial pins carrying said centering pivot and matrix reintocorresponding parts of the machine frame,

the threads of the pins and screws being so arranged that aunidirectional turning moment transmitted from the plate to said pinsand pivot and the pin 8 in a directions, the locking efiectscrews duringthe cutting operation will tend to cause an axial displacement of thepins towards each other and of the fastening screws away from each otherso as to also clamp the corresponding parts of the machine frame.

2. A centering device for cutting of disks in plate cutting machinescomprising a centering pivot, a matrix for cooperating therewith,coaxial pin carrying said centering pivot and matrix respectively andthreaded in opposite directions into fastening screws coaxial with saidpins and threaded in opposite directions into runners adjustable alongguide rails on the machine frame and adapted to be secured to the railsby means of said fastening screws, the threads of the pins and screwsbeing so arranged that a unidirectional turning moment transmitted fromthe plate to said pins and screws during the cutting operation will tendto cause an axial displacement of t e pins towards each other and of thefastenin screws away from each other.

3. A centering device for cutting of disks in plate cutting machinescomprising a centering pivot, a matrix for cooperating therewith,coaxial pins carrying said centering pivot and matrix respectively,parallelly extending guide rails on the machine frame, and runnersadjustable along 'said guide rails and carrying said pins the pinsbeing" threaded in opposite directions into the runner so that theturning moment imparted to the pins during the cutting operation willtend to cause an axial displacement of the pins towards each other andalocking of the runners to the guide rails.

EDVIN HAMPF.

